Role of the serotonin transporter gene and family function in adolescent alcohol consumption

Background: That the extent to which a particular individual will engage in problematic behaviors such as delinquency, violence, or drug abuse is determined by the way psychosocial, situational, and hereditary factors interact is widely accepted. However, only recently have researchers begun to investigate the interactions between specific genotypes and psychosocial factors in relation to behavior. The purpose of the present study was to investigate possible interactions between a polymorphism in the promoter region of the serotonin transporter (5-HTT) gene and family relations on adolescent alcohol consumption. Methods: A cross-sectional study with a randomized sample from a total population of 16- and 19-year-old adolescents from a Swedish county was conducted. Eighty-one male and 119 female adolescents, who volunteered to participate after having answered a questionnaire, were randomly selected from quartiles of volunteers representing various degrees of psychosocial risk behavior. Results: 5-HTT genotype (p = 0.029) and family relations (p 0.022) predicted alcohol consumption independently as well as through an interaction with one another (p = 0.05). The model explained 11% of the variance in alcohol consumption. In a binary logistic model, we found that adolescents with the LS variant of the 5-HTT gene and with family relations being neutral or bad had a 12- to 14-fold increased risk for high intoxication frequency. Conclusions: In sum, our results show that a functional polymorphism of the 5-HTT genotype, family relations, and interactions between these variables predict adolescent alcohol consumption in a randomized sample of adolescents.